DeWalt 20V Max battery not charging – any ideas?

Hey guys, I've got a DeWalt 20V Max battery that won't charge. It's about a year old, been working fine, but now the charger just blinks red. I tried different outlets, cleaned the contacts, but no luck. Anyone run into this?

Classic issue. Could be a dead cell or the BMS board. If you're handy, you can open it up and check the voltage on each cell. If one is below 1V, that bank is toast. Sometimes you can jump-start a deeply discharged cell with a 9V battery, but it's risky. If it's under warranty, I'd just exchange it.

I've had that happen before. First thing I try is freezing the battery for a few hours. Sounds crazy but it's worked for me twice. Take it out, put it in a ziplock bag (no moisture!), and freeze it for 4-6 hours, then let it warm up to room temp before charging. If that doesn't work, it's probably a bad cell.

Before you tear it apart, check the charger too. I had a charger that would blink red with any battery, turned out the charger was faulty. Borrow a friend's charger to test. Also, if the battery has a fuel gauge button, check if it lights up at all. If it's dead dead, could be a protection circuit trip.

Thanks for the tips, guys. I'll try the freezer trick first (why not?), then test with another charger. If that fails, I'll open it up and check cells. Appreciate the help!